pedestal mounted into lid/ switch


starting to work on wiring it up and getting the switch to work (which was a complete and total pain in the butt)


driver is a simple 2x AMC7135 board with 2 38K chips scavenged off a KD V2 3A board (it's cheaper than buying the things separately!). LED is a spare XP-G R5 CW (I think). I'm especially pleased with the tiny hex screws that I scavenged from an old microscope filter wheel :)
In place - the narrow tip of the pedestal was 5min epoxied into the black switch thing.

I decided to try and use parts of the existing switch, which was a good idea poorly executed. I spent several hours cutting and grinding those contacts until they didn't short against the heatsink (they still can if you give the light a sharp tap :(), actually separated when off, moved smoothly and so on and so forth. Not a lot of fun.
I decided to use the existing metal rod system to connect the driver/ LED to the battery in the base. My treasured Hakko iron came in handy here as I could crank up the heat to solder the nuts on the rods.

all connected

the tops of the rods had to be cut down as one of them was shorting against the driver somehow
now the battery :)
I had some 18650s spare from a recycled laptop pack that I thought I could use, plus a spare 3 cell holder, a PCB and a miniUSB li-ion charger board. It didn't quite work out well as the 18650s didn't seem to play nice with the PCB (high freq flickering for 3-4min before they settled down), so I had to use a spare protected 18650 instead.
battery holder

charger board

in place

close up of the charging port

with cover on

charging

light is red when charging, blue when charged. The holes are there to feed the vent at the bottom of the white plastic diffuser that the LED sits in, which vents out of the top, hopefully making some kind of "chimney" effect.
It works!

It was absolutely fantastic for camping. Enough light to play a board game on the picnic table or to get the kids into their PJs but not so much that it was too bright to read by. As far as I could tell by holding onto the little pedestal nub that pokes through the switch (must remember to measure more carefully next time! It was supposed to be flush with the top) it didn't get warm at all, even after being on for a couple of hours. Charging from the car charger was painless and we have a bunch of miniUSB wall warts around. I've converted one of my commuting bike lights to USB charging and the front one is next, it's just so convenient.
I'd like to figure out why those scavenged 18650s weren't working right as they fit that holder better and should give a ~6Ah battery instead of the 2.6Ah cell I have in there, which I also need for another project. I might try a different PCB when it arrives, just in case it was a duff one (previous one I bought from DX seems to work fine with another scavenged cell from the same pack).